Re: HVS-1 data


Terence O'Hanlon Smith
 

Ernst, and anyone to whom it may be of interest,

       after yesterday's dismal weather, with a SNR of near 8.0dB, and losses even of basic data, I took advantage of the sunny spell this morning to climb on the garage roof and tweak my 90cm dish and LNB.
 I used my and my wife's mobile phones on Facetime, one with it's camera on the BDAdatex window on the screen in my study, and the other with me on the garage roof. This made it possible watch any improvement in SNR as I adjusted the receptors.
From the 8.2dB with which the professional left me, I managed to obtain 11.3dB.
 What particularly took me by surprise was that, once the dish pointing and LNB focus and skew were near optimum, I was able to more finely improve th SNR by simply tightening or loosening each of the four bolts clamping the dish mount to the wall bracket. These theoretically only adjust azimuth, but by adjusting each bolt in turn I was able to further improve SNR by at least a half decibel. How sensitive is that!
    Anyway, thanks to y'all, particularly Ernst, for the heads-up, without which I would still be languishing in despair.
  Needless to say, by the time I came back indoors the data was flowing happily into the HVS-1 instance of Tellicast without me needing to touch anything else; so it appears, surprisingly,  that at least I had done everything correctly in software set up.
   ATB,
         Terence
  

On 09/11/2021 18:14, Ernst Lobsiger via groups.io wrote:
On Tue, Nov 9, 2021 at 09:33 AM, T-Online wrote:
everywhere i read that it is necessary to have min 12db signal strength for the HVS-1 Service....
With my 80cm dish i have all the time between 10.5 and 11.5db signal strength. I don't have with this setup any lost packages. Just in strong rainy conditions i am losing some packages.
Flo,

first of all we are talking about SNR not signal strength.
I also hope you only loose UDP packets not packages.

My above equations say that HVS-reception begins with about SNR = 9.3 dB. This is not on/off, you still have missed and lost packets.
The EUMETSAT recommendation of minimum 4 dB LM means they propose SNR >= 13.3 dB which is indeed rather high. This might
be intended for National Meteorological Services and should still work in not too heavy rain. I doubt you have no missed packets with
SNR between 10.5 and 11.5 dB. But it certainly works as your LM is between 1.2 and 2.2 dB (not below 0 dB as the one of Terence).

Cheers,
Ernst


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